Fig. 4: TLR4 deficiency reprograms macrophage polarization from pro-inflammatory to anti-inflammatory phenotype during sepsis.

A t-SNE plot showing clustering of myeloid cells into two macrophage subsets (macrophage_C1 and macrophage_C2) and neutrophils. B Quantification of myeloid cells composition. C Differential expression analysis of macrophage_C1 and macrophage_C2. D Distribution of macrophage_C1 and macrophage_C2 across experimental groups. E Scatter plot illustrating macrophage gene expression changes between the WT CLP and Tlr4^-/- CLP groups. F Venn diagram showing the overlap between upregulated genes in WT CLP and Tlr4^-/- CLP groups, compared to known M1 and M2 macrophage markers (sourced from OriGene’s M1 and M2 Macrophage Markers). The diagram illustrates the number of genes upregulated in each group, with the intersection highlighting genes shared across conditions. G Heatmap comparing the expression of key M1 markers (Il1a and Ccl3) and M2 markers (Arg1, Mrc1, and Cd200r1) between the WT CLP and Tlr4^-/- CLP groups. The Z-score of expression is plotted, with red indicating higher expression and blue indicating lower expression. WT CLP shows higher expression of M1 markers, while Tlr4^-/- CLP shows elevated expression of M2 markers. H Flow cytometry of macrophages isolated from BALF, showing percentages of iNOS⁺ and Mrc1⁺ macrophages across experimental groups. I, J Quantitative analysis of M1 and M2 macrophage proportions (n = 5). Data are represented as mean ± SD, *P < 0.05, ***P < 0.001.